Originally Posted by DyerNeedOfBeer
All of the replies so far seem to just reiterate the methods I mentioned above. I am still curious how someone could (for example) decide they need 10lbs of grain and 12 qts of water for the mash and 16 qts of sparge water and always hit a target gravity. Someone else could decide to use 10lbs of grain, 12qts of water for the mash, 12 qts of sparge water and then top off with water to the kettle. This would lend to a different O.G. due to the different ammount of sparging and change of efficiency due to it but I have failed to see this taken into account.
I am thinking that the only way to obtain consistency would be to sparge until the gravity of the runoff is the same each time regardless of how much sparge water is required and regardless of the preboil volumes and then adjust the volumes with either boiling or make up water.
No that consistency is something I am big on since I like the diverse tastes but I would hate to think that I calculate my recipe based on a grain volume then don't use enough sparge water or use too much and end up extracting tannins. I agree that the P.H. will control this but it is my understanding that once the runoff reaches these low gravities, the P.H. will be changing correspondingly.
I control consistency by controlling the variables. Attain the same temps for the same times during the mash, with the same amount and same types of grains. This allows me to have the same efficiency, which gives me the same amount of starch to sugar conversion, which gives me the same amount of sugars. By then rinsing with the same amount of sparge water and collecting the same amount of wort, I now have the same amount of gravity.
Maybe I am oversimplifying?